Airplane door construction



Jan. 4, 1938. 1 ZAND l 2,104,144

A IRPLANE DOOR` CONS TRUCTION Filed Sept. 26, 1935 '111111111111111 [l]lIl INVENTOR -BTYEPHE/v ZHN Patented 4, 1938 UNITEDl STATES PATENTOFFICE Sperry Gyroscope Company, Inc., Brooklyn,

N. Y., a corporation oi' New York ,l Application September 26, 1935,Serial No. 42,221

6 Claims.

This invention relates, generally, to the construction of airplanedoors, and the invention has reference, more particularly, to novel airsplane door construction wherein means is provided for effectivelysealing the door with respect' to its frame, thereby preventing noiseand outside air from access to the airplane interior or cabin.

Heretofore, considerable diiliculty has been encountered in sealingairplane doors against objectionable noise and air currents, the latterbeing especially pronounced when flying from one altitude to-another.Gaskets have heretofore been used in connection wthairplane doors, butsuch gaskets leak due not only to varying outside air pressuresresulting from the flying of the plane at various altitudes, but alsodue largely to the flexible or yieldable nature of the fuselage and thedoor frame carried thereby. Thus, while the door is generally ofnecessity built strong enough to withstand changes in air pressureresulting from changes in altitude, the fuselage and thedoor framecarried thereby are vapt to yield, permitting passage of air and noisepast the door gasket and into the cabin as well as permitting the escapeof air therefrom, all of which is highly objectionable.

The principal object of the present invention 4 is to provide anovellairplane door construction 80 and particularly sealing meanstherefor which serves to effectively prevent the transmission of air andsound past the line of juncture ofthe airplane door and its frame.

Another object of this invention lies in the provision of anovel'airplane door construction of the above character wherein gasketmeans is employed that is responsive to variations in atmosphericpressure due to varying altitudes and serves to effectively seal thedoor within its frame regardless of the altitude of night and regardlessof the flexibility or yieldability of the airplane fuselage and doorframe.

Modern airplanes ily at altitudes of seldom less than 3000 feet andlargely at 8000 feet, and the substantial pressure difference betweenthese altitudes and that at ground level is employed in the novelconstruction of the present invention for eiectively sealing theairplane door.

Other objects and advantages will become apparent from thespecification, taken in connection with the accompanying drawing whereinone embodiment of the invention is illustrated.

In the drawing. 55 Fig. 1 is a fragmentary perspective` viewof a typicalairplane employing the novel'door construction of this invention.

Fig. 2 is an enlarged transverse sectional view, with parts broken away,of the door and the surrounding door frame or cabinl wall structureemployed in the airplane of Fig. 1, and

Fig. 3 yisan enlarged fragmentary view of a. portion of the structure ofFig. 2.

Similar characters of reference are used in the above iigures toindicate corresponding parts. 10

Referring now to the said drawing, the referenceV numeral I designatesan airplane having a cabin door 2 designed and constructed for receivingthe novel sealing means of this invention. The door 2 is similar. incross-section to a refrigerator door in that a transverse or verticalsection thereof has the shape of a trapezium,

las shown in Fig. 2, the same being hinged, as by hinges 3, to the doorframe or surrounding cabin structure 4, forming a part vof the air- 20plane fuselage or cabin. The door 2 is shown as consisting of inner andouter panels 5 and 6 which are shown interconnected at intervals byspacing members or plates 'l which are preferably disposed diagonallywith respect to the 25 panels 5 and 6. Insulation 8, in the form offeltf ed material, is illustrated as confined within the hollow interiorof thedoor 2 and frame 4 and extends between panels 5 and 6. v

According to the preferred arrangement, the 30 diagonally inclined jambportion `of door frame 4 and the similarly inclined opposed door edgeportion 9 are provided with complementary pockets or grooves I0, II,respectively, which pockets or grooves taken together are of circularcross 35 section. Although preferably these opposed pockets or groovesI0, II are shaped to thusly define a cylindrical passage or recess I2extend ing completely around the door, which passage is shown ofcircular cross section, yet it is to be 4,0 understood that this passageI2 may be of other suitable cross sections, such as elliptical.Preferably, the complementary pocket or groove I0 provided in the doorframe or cabin wall 4 is of somewhat larger area than the pocket II pro-45 Avided in the edge portion of the door.

Extending within the cylindrical passage II2 is a pneumatic tube I3which may be of rubber or other suitable flexible material, the samebeing formed with outwardly directed flanges Il for matic valves i8,similar to tire valves, extend from the interior of the fuselage o rvcabin into the pneumatic tube i3, thereby enabling the air pressurewithin the tube I3 to be controlled from within the cabin.

Thus, it will be noted that the pneumatic tube i3 is carried by thevdoor frame and is xed within the pocket i0 of such frame, said tubehaving a convex projecting portion I3' extending into the pocket Iiprovided in the edge portion of the cabin door 2. The door 2 isfurnished with the usual operating handles and lock or locks.

In use, the pneumatic tube il occupying the passage or space i2preferably contains air at normal atmospheric pressure, the air havingbeen admitted thereto with the piane on the ground by merely openingvalve i6 and allowing air to enter the tube from the atmosphere, so thatthis tube assumes its normal circular or other intended shape. Since thetube thusly contains air at atmospheric pressure only, it is very easyto open the door with the airplane on the ground. inasmuch as the airpressure within the tube vis the same as that on the outside, therebypermitting the projecting portion Il' oi' the tube to give way to themovement of the door. As the airplane ascends, however, the atmosphericpressure surrounding the plane will gradually decrease, and since thepressure within tube i3 remains constant, this tube will tend to expandand thereby`rmly tlt between the opposing walls of pockets i0 and ii,thereby, securely sealing the joint between the door and its frame.

Thus, it will be seen; that the pneumatic tube i3 is caused to conformto and ilrmly press both upon-the door and upon the door frame duringnormal iiight and serves not only to eiectively seal the door againstingress and egress of air currents and sound regardless of anymisalignment of the door yand its jamb due, for example. to ilexure ofthe ,cabin walls, but the tube i3 also acts as an additional lock toprevent the acci-v air pressure within tube i3 and hence' is vprevented'from yielding, so that the door cannot be opened accidentally while theplane is in flight. i

In the event that it is desired to open the door while in iiight, as forthe purpose of making a parachute jump or emergency exit, the valve IIcan be opened from within the cabin and the air pressure withinpneumatic tube i3 released thereby enabling the-door to be opened.

If desired, the pneumatic tube i! may be only partially inilated whenthe airplane is on the ground, especially when the piane is to tly atvery high altitudes, thereby causing the projecting portion i3' of thepneumatic tube to be deilected inwardly somewhat, as shown in dash linesin Fig. 3, and designated by the reference numeral i3". In this eventthe door will be extremely easy to open when the plane is on the ground.while at the same time, when ilying at high altitudes, the pressurewithin the tube i3 will be suillcient to greatly expand the sarneso thatits portion i3"` abuts firmly -against the grooved edge portion of thedoor.y On the other hand, if

the plane is to normally ily at comparatively low altitudes, `the tubei3 may be initially inilated to somewhat more than normal atmosphericpressure by means of a suitable pump applied to' valve or valves |,6, inwhich case the juncture between the door and its frame willbeeffectively sealed by tube il at low ilying altitudes. -Ifdesired', thevalves It may extend tothe outside in- Y stead of the inside of thecabin, in which case suitable mechanism would be employed for open-l ingthese valves from within the cabin.

Asmany changes` could be made in the above w construction and manyapparently widely difierent embodiments of this invention could be madewithout departing from the scope thereof, it is intended. that allmatter contained in the above description or shown in the accompanyingdrawmeans connected to saidA tube to enable the changing of the airpressure within the same, so

that upon landing the door may be opened at will, with the tube thenserving as a cushion.

2. In a seal for a cabin door of an airplane, the

combination with said door, a frame surrounding said door, said doorhaving a groove extending around its marginal edge portion, said doorframe having its jamb. portion provided with a complementary groove foropposing the groove of said door, said door and said jamb portiongrooves jointly providing a passage of substantially circularcross-section extending about said.

door, and a pneumatic tube contained within said passage, and means forinfiating said tube.

3. In a seal for a cabin door of an airplane, the combination with saiddoor, a frame surrounding said'door, said door having a groove extendingaround its marginal edge portion, said door frame having its jambportion provided with a -complementary groove vfor opposing the grooveof said door, said door and said jamb portion grooves jointly providinga passage oi' substantially circular cross-section extending about saiddoor, and a pneumatic tube contained Within said passage and attached tosaid jamb portion, the larger part of said tube being contained withinsaid jamb. portion groove for facilitating the opening oi' thev door.

4. In a seal for a'cabin door oi'l 'an airplane,

the combination with a door of substantially trapezium cross-section, adoor frame having a` door opening of trapezium cross-section forconformably receiving said door, the peripheral portion oi' said doorand the jamb portion oi said door frame having complementary. opposedgrooves, the groove of said door frame jamb portion being of larger areathan that of said door,

la pneumatic tube within said door frame. jamb portion Vgroove forprojecting into said door grooves to seal the Joint between said doorand its door frame, and valve means connected to said tube for enablinga desired air pressure to be provided therein. Y

5. An airplane cabin door as claimed in claim 2, in which said tube ispartially collapsed at `the ground level prior to takeoil, but containssuillcient air to become inflated at normal cruisging levels without theaddition ci' air therein.

6.6In an airplane, a door and a surrounding 76 door vframe structure.said door and said door frame structure having opposing groeves forproviding a passage extending about the door. and a. pneumatic tubewithin said passage. the air pressure within Vsaid tube being such as toen- 5 able the door to be readily opened with the craft on the ground,the decrease in atmospheric pressure resulting from an ascent of thecraft causing air within said tube to expand, whereby said tubeeectively seals the joint between the door and its frame. f

STEPHEN J. ZANDB

